Development Of Vehicle Control Unit Hardware-in-loop Testing System And Research On Driving Control Strategy For Pure Electric Vehicle

Vehicle control unit is the core component of pure electric vehicles， bearing the func-tion of the controlling of vehicle power system and energy management, and it is an impor-tant guarantee for pure electric vehicles to achieve the target of high efficiency, reliabilityand safety. The vehicle control strategy is responsible for coordinating work between variouscomponents of pure electric vehicle powertrain, playing a decisive role in the pure electricvehicle’s dynamic characteristics, fuel economy and safety. Electric vehicle control strategyincludes driving control strategy, braking control strategy, energy management control strat-egy and safety control strategy. The driving control strategy controls the vehicle powertrain,which is the main research content of the vehicle control strategy.Hardware-in-loop Testing System provides a virtual vehicle running environment forvehicle control unit, which can test the hardware functions of vehicle control unit, the controllogic of software and timing sequence of control system comprehensively. It also can testwhether the control strategy meets the requirements, and realize the calibration and optimi-zation of the key parameters in control strategy.Therefore, Hardware-in-loop Testing System can improve the vehicle control unit de-velopment efficiency, reduce development costs, improve the design quality of the vehiclecontrol unit, and avoid the risk of vehicles being recalled.Combining with the actual project’s need, the paper focuses on the driving controlstrategy for pure electric bus and the vehicle control unit hardware in loop test system. Thethesis’s main research content includes:1. Analysis the structure of the pure electric bus power system and elaborate the func-tion of vehicle’s control system. According to the experimental data of driving motor andbattery and combining the vehicle state and operation condition, the pure electric bus’s driv-ing process is divided into starting mode, economic mode, dynamic mode and limp mode. Considering the vehicle’s driving performance, fuel economy, safety and drivability, thisthesis puts forward a completely feasible strategy on driving control strategy of pure electricbus.2. Using Matlab/Simulink, build pure electric bus’s forward simulation model, includ-ing vehicle model, power battery model, motor model and driver model. At the same time,complete the driving control strategy’s implementation in Simulink, and then the drivingcontrol strategy is simulated. Simulation results show that the motor’s driving torque canpreferably follow the accelerator pedal’s opening change, the torque can adjust sensitively.Vehicle handling is good. This strategy can analyze and execute the driver’s intention, so thevehicle can run safely.3. Research and develop vehicle control unit hardware in loop test system based on xPCTarget. Based on the function analysis of test system, put forward a general structure schemeof the test system, then complete the design and development of test system’s software andhardware and system integration.4. The vehicle control unit and driving control strategy proposed in this paper is testedby hardware-in-loop testing system before using in the bus. After the completion of the test,driving control strategy is tested in the real vehicle road test. Results show that the drivingcontrol strategy is feasible and effective, and can better parse the driver’s operation intention.Under this strategy, vehicle has good driving performance and can reduce vehicle energyconsumption level under the premise of driving demand, at last the travel distance is in-creased.